This research program aims to develop catalytic synthetic methods that form amines, ethers and sulfides and to obtain precise mechanistic information for the design of new catalysts and for deducing relationships between emerging catalytic processes that form C-N, C-O and C-S bonds and related catalytic processes that form C-C or C-H bonds. The proposed research focuses on several synthetic methods that have become widely utilized and that have inspired other groups to develop related chemistry. Each of the specific aims of this proposal focuses on developing a firm mechanistic platform from which we will build new catalysts and reaction processes. One portion of the proposed research will focus on the development of a new generation of palladium catalysts for the coupling of amines with aryl halides using data on the factors that control catalyst initiation, the rates of individual steps of the catalytic cycle, and equilibria that control selectivity. A second portion of the proposal will establish a mechanistic understanding of copper-catalyzed couplings of aryl halides with nitrogen and oxygen nucleophiles and the use of this information as inspiration to develop catalysts for the formation of aryl carbon-heteroatom bonds using other metals. A third portion of the proposed research will focus on a recently discovered type of rhodium catalyst that promises to significantly increase the scope of alkene hydroaminations. These studies will use recent structural data to understand the mechanism of this process and to design new catalysts. A fourth portion of the research will focus on enantioselective methods to prepare allylic amines and ethers. Again, recent structural data will be used to understand the mechanism of the reaction and to design catalysts that react with classes of reagents that have not been encompassed by this process previously. Thus, the proposed research will significantly advance reactions with organometallic catalysts to form the carbon-heteroatom bonds in pharmaceutically important materials, while demonstrating approaches to use mechanistic data in the design and development of new organometallic catalysts that increase the efficiency, diversity and capability of organic synthesis.